Laser killing of ABp creates a barrier between contact with the C and the ABar blastomeres in Caenorhabditis elegans embryos

The ABp blastomere (red x) was laser killed at the four-cell stage of embryogenesis, just before the start of the movie. The corpse of ABp prevents contact between the C blastomere (membrane near closest contact outlined in blue) and the ABar blastomere (membrane near closest contact outlined in green). Focal depth (10.5 μm) of closest proximity between the two blastomeres is shown. As a result, the ABar blastomere aligns its spindle in the default orientation (line) and divides parallel with the other AB granddaughter cells (not shown). Supplemental movie from Imaging in Developmental Biology: A Laboratory Manual, Cold Spring Harbor Laboratory Press.]